In many fields of industrial laser material machining there exists the desire to have compact laser devices, in which the waste heat is transferred by means of simple gas or air cooling. In comparison to the water cooling that is often used, gas or air cooling has the advantage that the number of components involved in the cooling circuit can be significantly less, and as a result, the risk of failure of the laser device can be dramatically reduced. For the laser beam source of the laser device, air cooling signifies the elimination of potential water leakages, and therefore reliability of the laser device can be increased with air cooling.
In water-cooled laser devices, the laser beam source is located in a laser head and its power supply unit is located in a separate power supply device, in which a central cooling unit is also located. The power dissipated in the laser head, together with the power loss occurring in the power supply device, is transferred by means of a water circuit to the cooling unit and is there delivered up to the surroundings through a heat exchanger. In the water cooling for this configuration there is usually only a single location at which heat exchange takes place, namely at the power supply device. Since water is a relatively good heat transfer medium due to its thermal capacity, the heat can be transferred very efficiently from the laser head and its build volume can be configured to be correspondingly compact.
In comparison with this system convective heat removal from the laser head by means of gas or air is fundamentally less efficient, in spite of its advantages with regard to its compactness. In air-cooled laser equipment, conventional ribbed metal cooling elements with a high heat transfer resistance can be used. These cooling elements usually have only a single cooling surface and a large build volume. However, the large build volume and the constrained options for installing these cooling elements limit the compactness of the laser head and restrict the design options substantially. The use of commercial cooling elements for the laser head usually inhibits cooling efficiency on the one hand, and compactness and design freedom.